Hierarchical flower-like MnPS3 hollow spheres for high-rate and long-cycle sodium storage

Abstract

Transition metal phosphorus trisulfides (MPS₃) are promising sodium-ion battery anode materials because of the unique layered van der Waals structure, diversiform composition, and high theoretical specific capacity. Nevertheless, their practical application is still hindered by poor rate and cycling performance, primarily due to their intrinsic characteristics of low electrical conductivity and susceptibility to pulverization. In this study, hierarchical flower-like MnPS₃ hollow spheres (MnPS₃ HSs) are prepared by phospho-sulfurization of Mn-glycerol solid spheres through Kirkendall effect. The appealing architecture of MnPS₃ HS, characterized by large hollow cavities and three-dimensional vertical nanosheet arrays, results in an increased specific surface area, shortened ion transport distance, and accelerated charge transfer rate. These positive effects collectively enhance the rate and cycling performance of MnPS₃ HS. The prepared MnPS₃ HS affords high specific capacities of 521 and 328 mAh g⁻¹ at 0.1 and 5 A g⁻¹, and an outstanding cycling stability with a retention of 92.6 % after 1000 cycles at 2 A g⁻¹. In the full-cell system, a high capacity retention of 97.5 % after 500 cycles is also maintained. These results provide significant insights into advancing the sodium storage performance of MPS₃-based anodes through the design of a three-dimensional hollow structure.